Howdy, so I am racing to get some boxes made for Christmas gifts. I am trying to cut the 45 degree miters on my table saw using a cross-jig. I clamp the work piece in place and use stop blocks, but I get an odd U shape to the cut. The board is milled flat and square prior to making the cut. Any idea what is happening here? My blade is calibrated to the miter slot and my rip and parallel cuts are fine. It is just these miters that are killing me. Ideally I would use a shooting board, but I don't have one and I don't have time to make one before Christmas. Any help would be amazing.